1. Field of the Invention
This invention generally relates to syringes and more particularly pertains to syringes which cannot be reused.
2. Brief Description of the Prior Art
In the usual practice, non-reuse of the single-use type syringe is left to the good will of the users. In recent times however the requirement to prevent actual reuse has become more acute as the practice, customary in environments like that of drug addicts, has become very risky due to the spread of infectious diseases.
Several types of technical measures have thus been proposed to make self-locking syringes non-reusable after a first use. The solutions proposed by the known art however display technical features which make said syringes complicated and costly to produce as well as often difficult for the user to handle and unsatisfactory in operation. For example there have been proposed syringes wherein the cylindrical body which receives the liquid is internally equipped with stops for locking the thrust piston once it has reached complete insertion condition after injection of the liquid taken in. The presence of said stops on the sliding walls of the piston seal has however various drawbacks, a general loss of seal between the piston and the syringe body being of primary concern. (see for example U.S. Pat. No. 4,995,869) In addition it is always preferable that the part of the syringe which receives the liquid to be injected be as smooth as possible and free of roughness.
The general purpose of the present invention is to overcome the above mentioned drawbacks by offering a self-locking single-use syringe with provisions which would prevent reuse thereof and would also be simple and economical to produce as well as easy for the user to use, at the same time providing a receiving part for the liquid to be injected substantially similar to that of a normal syringe.